1. Field of the Invention
The invention relates to a magnetic tape provided with a track configuration comprising a track zone with adjacent inclined tracks, which extend obliquely relative to the longitudinal direction of the tape, which can be scanned by means of rotationally drivable magnetic heads and which serve to store information signals, and a control signal track, which extends in the longitudinal direction of the tape and is adjacent to the track zone and in which a control signal can be stored, the length of a recorded signal period of said control signal being proportional to the distance in the longitudinal direction of the tape between two inclined tracks which can be scanned by the same magnetic head, and each signal edge of said control signal being associated with an inclined track.
The invention also relates to an apparatus for cooperation with a magnetic tape of the type defined in the first paragraph, which apparatus is adapted to record signals on the magnetic tape and comprises rotationally drivable magnetic heads for scanning the inclined tracks on the magnetic tape, a stationary magnetic head for scanning the control track on the magnetic tape, and a control signal generation device adapted to generate and supply at least one control signal to be recorded in the control signal track on the magnetic tape, the length of a recorded signal period of said control signal being proportional to the distance in the longitudinal direction of the tape between two inclined tracks which can be scanned by the same magnetic head, and each signal edge of said control signal being associated with an inclined track, the control signal generation device having an output for supplying the control signal to be recorded.
The invention further relates to an apparatus for cooperation with a magnetic tape of the type defined in the first paragraph, which apparatus is adapted to reproduce signals from the magnetic tape and comprises rotationally drivable magnetic heads for scanning the inclined tracks on the magnetic tape, a stationary magnetic head for scanning the control track on the magnetic tape, and a control signal processing device adapted to receive and process at least one control signal reproduced from the magnetic tape and having at least one input for receiving said reproduced control signal and at least one output for supplying a processed control signal.
2. Description of the Related Art
A magnetic tape of the type defined in the first paragraph, an apparatus of the type defined in the second paragraph, and an apparatus of the type defined in the third paragraph are known, for example, particularly from the magnetic-tape-cassettes and magnetic-tape video recorders in accordance with the VHS standard which are on the market practically all over the world. In accordance with this standard, information signals, in the form of analog video signals and, if desired, analog audio signals, can be stored or have been stored in the inclined tracks of a magnetic tape. In a first longitudinal track which extends in the longitudinal direction of the tape, which track is intended for the storage of further information signals, analog audio signals can be stored or have been stored as further information signals. In a second longitudinal track, which also extends in the longitudinal direction of the tape, a control signal of a given frequency f.sub.1 can be stored or has been stored, which control signal is generally referred to as a CTL signal and, in accordance with the VHS standard, is formed by a squarewave signal. This CTL signal is basically generated in relation to the vertical synchronization pulses of an analog video signal to be recorded in the inclined tracks, in such a manner that it has a frequency value f.sub.1 which bears a given relationship to the value of the picture frequency. The frequency f.sub.1 is equal to half the frequency of the vertical synchronization pulses. The length of a recorded signal period of the CTL signal is equal to the distance in the longitudinal direction of the tape between two inclined tracks which can be scanned with the same rotationally drivable magnetic head. Each rising edge of the CTL signal is assigned to a given inclined track, namely to an inclined track in which the signals have been recorded with a given azimuth angle, i.e., an azimuth angle of -6.degree.. During the reproduction of recorded video signals, the CTL signal recorded in the second longitudinal track serves as frequency and phase information for a speed control device for controlling the speed of a drive motor for a capstan to drive the magnetic tape with a constant tape speed, and also as information when each of at least two rotationally drivable magnetic heads for scanning the inclined tracks enters into or is in scanning contact with an inclined track. During reproduction of video signals stored in the inclined tracks, the likewise reproduced CTL signal is applied to the speed control device for the capstan motor, the frequency of the CTL signal being compared with a nominal value to control the speed of the capstan motor, depending on the result of the comparison, in such a manner that the video signals and, if present, audio signals stored in the inclined tracks are scanned and reproduced properly and in a faultless manner by means of the rotationally drivable magnetic heads.
The Applicant has started the development of a new video recorder system for recording and reproducing video signals and audio signals on/from magnetic tapes in accordance with the VHS standard, which system enables not only analog video signals and analog audio signals but also digital video signals and digital audio signals to be stored in the inclined tracks. This new video recorder system is described, for example, in the nonpublished Austrian Patent Applications filed under numbers A 1555/94 and A 1971/94, herewith incorporated by reference. When, by means of this new video recorder system a CTL signal is recorded in the second longitudinal track in a manner in accordance with the VHS standard, the problem arises that in the case that a magnetic tape, on which digital video signals and digital audio signals have been stored in the inclined tracks and the CTL signal associated with these digital signals has been stored in the second longitudinal track, is loaded into a known video recorder in accordance with the VHS standard, the magnetic tape is driven with a tape speed corresponding to the stored CTL signal and influenced by this CTL signal, the digital video signals and digital audio signals stored in the inclined tracks then being reproduced by the rotationally drivable magnetic heads of the known video recorder which is constructed in accordance with the VHS standard. However, such a known video recorder in accordance with the VHS standard is not constructed for a proper and faultless processing of these digital signals. An undesirable consequence of this is that the digital video signals and digital audio signals reproduced by means of the rotationally drivable magnetic heads are also applied to the audio signal processor of the known VHS video recorder, in which the digital signals may be processed as analog audio signals, which may result in an undesirable and annoying acoustic reproduction.